Puppet-valve.



C. A. FFANSTSEHL.

PUPPET VALVE,

APPLICATION-FILED MAR. 7. 1912.

Patented Oct. 29, 1918.

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UNITED STATES PATEN OFFICE.

CARL A. PFANSTIEHL, or HIGHLAND PARK, LLINOIs, AssIeNon 'ro PFANsTIEIICOMPANY, me, or NORTH CHICAGO, ILLINoIs, A CORPORATION OF NEW YORK.

PUPPET-VALVE.

Specification of Letters Patent.

Patented Oct. 29, 1918.

Application filed March 7, 1917. Serial NO. 152,973.

To all whom it may concern:

Be it known that I, CARL A. PFANSTIEHL, a citizen of the United States,residing at Highland Park, in the county of Lake and State of Illinois,have invented a certain new and useful Improvement in Puppet- Valves, ofwhich the following is a full, clear, concise, and exact description,reference being had to the accompanying drawings, forming a part of thisspecification.

My invention relates to a puppet valve in which the head is made oftungsten or other high speed steel and in which the stem is made ofsteel having the expansive characteristics of 31} per cent. nickelsteel.

Both tungsten and molybdenum high speed steel have very highco-efficients of expansion by reason of which valves made wholly of highspeed steel have been found to be objectionable because of the greatexpansion of the head and stem under the excessive heat at which theexhaust valves 01' internal combustion engines are operated in practice.In order that the expansion of tungsten steel valve stems will notinterfere with the proper operation of the valve after the stem hasbecome highly heated from the exhaust gases the stems must be quiteloosely fitted within the sleeves in which they reciprocate and mustalso be adjusted with such a wide clearance between the ends of thestems and the tappets that noise invariably results when the engine isbeing run under light load or under such conditions that the valve stemsare not excessively heated.

The expansion of the tungsten steel valve head causes the valve to riseslightly upon its tapered seat, but this is insuflicient to compensatefor the expansion of a tungsten steel stem. Tungsten steel is also avery good conductor of heat and, therefore, although the burned andburning gases only impinge upon the stem at points near the head theentire stem becomes heated to a greater extent than the surroundingiron.

Nickel may be alloyed with steel in such proportion as to substantiallyeliminate expansion. The United States standard measures are made ofthirty-six per cent. nickel alloy steel, this alloy having a lowerco-efficient of expansion than any other alloy of ordinary metals known.By lessening the proportion of nickel any degree of expansion from thatof pure iron to that of thirtysix per cent. nickel can be secured.

It has been found experimentally that a stem containing substantially311- per cent. of nickel compensates perfectly for the difference inoperating temperatures between the stem and the surrounding cast iron ofa water cooled engine. In order to provide a stem which will change inlength between the valve seat and the end of the stem for thetemperature at which the valve head and stem are operated to exactly thesame amount as do the cast iron portions at the much lower temperatureat which they are operated due consideration must be given to the factthat the lateral expansion of the valve head causes the head and upperend of the valve stem to rise, due to the slope of the valve seat. Itwill be apparent that the proportions of nickel in this alloy must bevaried for different lengths of valve stems and for different facilitiesfor carrying off the heat from the lower portions of the stem, butexperiments show that two per cent. to five per cent. nickel componentin the alloy will compensate for the expansion in all of the knowncommercial types of puppet valves.

, My invention is illustrated in the accompanying drawing upon which thehead is designated as high speed steel and the stem is designated as 3nickel steel. It is to be understood that I contemplate such proportionsof nickel as will compensate for the difference in temperature betweenthe valve and stem and its supporting parts for any valve of similardesign to that illustrated in the drawing. The valve head and stem arepreferably fused together by the process set forth in my applicationentitled puppet valves, Serial No. 138,7 80 filed December 26, 1916..

Having thus described my invention what I claim as new and desire tosecure by Letters Patent of the United States is:

1. A valve having a tungsten steel head and a stem of substantially 3?;per cent. nickel steel.

2. A valve having a high speed steel head and a steel stem containingfrom 2 to 5 per cent. of nickel homogeneously attached to said head.

3. An exhaust valve for engines having a head of high speed steel and astem of an my name this 28 day of February, A. D. alloy having aco-eificient of expansion suf- 1917. ficiently less than cast iron tocompensate for the diflerence in operating temperature 5 between thevalve stem and the supporting Vitnesses:

parts of the engine. MARGARET GROBBEN,

In Witness whereof I hereunto subscribe G. L. PAULLIs.

CARLA. PFANSTIEHL.

Copies of this patent may be obtained for fire centseach, by addressingthe Gommissloner of Patents,

' Washington, I). O.

